1. Field of the Invention
The present invention relates to (i) a cartridge, which receives therein fluid material such as adhesive, calking agent for constructional purposes, mayonnaise, ketchup or the like and is fitted in a fluid dispensing apparatus, i.e., a fluid dispensing gun for a practical use, (ii) an assembly including such a cartridge and (iii) a method for manufacturing such a cartridge.
2. Description of the Related Art
With respect to such a kind of cartridge for a fluid dispensing apparatus, there has conventionally been known a can-like container made of paper (hereinafter referred to as the xe2x80x9cpaper canxe2x80x9d) 1 as shown in FIG. 10. The paper can 1 has a cartridge body 2 having a tubular shape, a nozzle provided at the front end of the cartridge body 2 and a bottom 4 provided at the rear end of the cartridge body 2 so as to be slidable along the inner peripheral surface of the cartridge body 2. FIG. 11 shows a fluid dispensing apparatus 5 in which the paper can 1 is to be placed. The fluid dispensing apparatus 5 is composed of a grip 7, a support member 10, an end plate 8 and a piston 9. The support member 10 has a semi-cylindrical shape and extends forward from the upper end of the grip 7 to support the cartridge, i.e., the paper can 1. The end plate 8 has a horseshoe shape and is provided at the front end of the support member 10. The end plate 8 can come into contact with the discharging end side of the paper can 1. The piston 9 pushes the bottom 4 of the paper can 1 to move it. When the paper can 1 is fitted in the fluid dispensing apparatus 5 and a trigger lever is pulled, a piston disk 6 provided in the fluid dispensing apparatus 5 pushes the bottom 4. As a result, fluid material such as adhesive or the like with which the paper can 1 is filled, is squeezed from the nozzle 3.
The cartridge body 2 of the paper can 1 has a high rigidity. The paper can 1 in which fluid material received in it has been used up is subjected to disposal as waste without collapsing it. This may lead to an enormous waste amount of paper cans 1, causing social problems of waste disposal. In order to solve such problems, there has conventionally been proposed a cartridge for a fluid dispensing apparatus as shown in FIG. 12, having a sausage-shape, which can be squeezed by the piston disk 6 to decrease the volume of the cartridge. The cartridge 13 for a fluid dispensing apparatus is formed of a plastic film into a film shell 13a having a tubular shape. The front and rear ends of the film shell 13a are closed by means of fasteners 13b, 13b such as relatively heavy metallic wires. The cartridge 13 with the front end portion near the fastener 13b cut is fitted in the fluid dispensing apparatus 5 in practical use and the piston disk squeezes the rear end of the cartridge 13. When such a sausage-shaped cartridge 13 for a fluid dispensing apparatus is used, a fluid dispensing apparatus having a nozzle is applied as the fluid dispensing apparatus 5.
There is known a cartridge assembly for a fluid dispensing apparatus as shown in FIG. 13, in which the volume of a cartridge can be decreased through a squeezing operation (see Japanese Laid-Open Patent Application No. H7-1711,461). The cartridge assembly is composed of a cartridge 19 and an outer tube 18. The cartridge 19 is provided with a film shell 15 having a tubular shape and molded portions 16, 17 provided at the opposite ends of the film shell 15, respectively. Formation of the molded portions 16, 17 is carried out by an injection molding method. The outer tube 18 has a tubular shape and can receive the cartridge 19 in it. In such a cartridge 19, the film shell 15 is formed into a tubular shape, and then, the molded portions 16, 17 are provided at the opposite ends of the film shell 15 by carrying out an insert injection forming method or joining pre-formed parts to the opposite ends of the film shell 15. The molded portion 16 at the front end of the film shell 15 has a discharging opening 16a from which fluid material can be discharged. A nozzle (not shown) may be screwed to the discharging opening 16a. The cartridge assembly 14 is fitted in a fluid dispensing apparatus when used. The piston disk pushes the molded portion 17 locating at the rear end of the film shell 15 so that the molded portion 17 slides in the outer tube 18. As a result, the cartridge 19 is squeezed. The outer tube 18 can be used repeatedly.
However, in the conventional sausage-shaped cartridge 13 as shown in FIG. 12 for a fluid dispensing apparatus, the cartridge 13 does not have a sufficient strength and deep wrinkles occur at both the front and rear ends of the film shell 13a when fluid material is squeezed from the cartridge 13, which has been fitted in the fluid dispensing apparatus. A relatively large amount of fluid material is left between the deep wrinkles, thus causing a problem. The excessively deep wrinkles may cause clogging of the nozzle of the fluid dispensing apparatus.
In the conventional cartridge assembly as shown in FIG. 13 for a fluid dispensing apparatus, the molded portions 16, 17 has a sufficient strength, but the film shell 15 does not have a sufficient strength and deep wrinkles occur on the film shell 15 as shown in FIG. 14. A relatively large amount of fluid material is left in a gap P between the deep wrinkles, thus causing a problem. The molded portions 16, 17 forms the opposite ends of the cartridge 19. Consequently, even when the film shell 15 is collapsed, the volume of each of the molded portions 16, 17 remains unchanged, leading to limitation of the total volume of the collapsed cartridge 19. In addition, two steps, i.e., the formation step for the film shell 15 and the molding step for the molded portions 16, 17 are required, leading to complicated manufacture of the cartridge assembly.
An object of the present invention is therefore to provide a cartridge for a fluid dispensing apparatus, which can be formed only of a film without carrying out a molding method and prevent any deep wrinkles from occurring when squeezed by means of the fluid dispensing apparatus, a cartridge assembly including such a cartridge and a method for manufacturing such a cartridge.
In order to attain the aforementioned object, in a cartridge of the present invention for a fluid dispensing apparatus, a film bottom member folded into a V-shape is provided at the rear end of a film shell having a tubular shape. More specifically, the cartridge of the present invention comprises: a film shell having a tubular shape; and a film bottom member provided at a rear end of said film shell in a longitudinal direction thereof, said film bottom member being capable of being folded into a V-shape along a folding line or of being unfolded so as to expand at a central portion of said folding line in a transverse direction of said film shell, by filling said cartridge with fluid material.
According to the present invention described above, it is possible to manufacture the cartridge for a fluid dispensing apparatus only with the use of a film without carrying out a molding method. As a result, a lamination structure may be applied to the cartridge and incorporation of a film having for example an excellent barrier property into the lamination structure makes it possible to apply the cartridge to storage of foods to be received. The film bottom member, which forms the rear end of the cartridge for a fluid dispensing apparatus, can be folded into a V-shape or unfolded so as to expand at the central portion of the folding line in the transverse direction of the film shell, thus increasing the strength of the bottom. This makes it possible to prevent deep wrinkles from occurring on the bottom of the cartridge for a fluid dispensing apparatus. In addition, the strength of the rear end portion of the cartridge can also be increased, thus providing an appropriate seating state of a piston disk of the fluid dispensing apparatus against the rear end of the cartridge.
The above-mentioned film shell may have a joint portion, which is formed by joining opposite side edges of a rectangular flat film to each other, said joint portion extending from the rear end of said film shell to a front end thereof in the longitudinal direction of said film shell. According to such an optional feature of the present invention, the joint portion serves as a strut for the film shell, thus increasing the strength of the film shell. It is therefore possible to prevent deep wrinkles from occurring on the film shell when squeezing the cartridge for a fluid dispensing apparatus.
The above-mentioned joint portion may pass through a place corresponding to the central portion of said folding line of said film bottom member. According to such an optional feature of the present invention, the joint portion serving as the strut increases the strength of the film shell in balance.
In order to attain the aforementioned object, the other cartridge of the present invention for a fluid dispensing apparatus, comprises a film shell having a tubular shape; and a nozzle provided at a front end of said film shell in the longitudinal direction thereof, said nozzle being formed by sealing said front end of said film shell to provide a nozzle member, and then cutting a tip end of said nozzle member. According to such a feature of the present invention, it is possible to manufacture the cartridge for a fluid dispensing apparatus only with the use of a film without carrying out a molding method. The nozzle provided at the front end of the film shell prevents deep wrinkles from occurring on the front end of the film shell when squeezing the cartridge.
In order to attain the aforementioned object, a cartridge assembly of the present invention for a fluid dispensing apparatus, comprises: a cartridge for a fluid dispensing apparatus, comprising (i) a film shell having a tubular shape, said film shell having a joint portion, which is formed by joining opposite side edges of a rectangular flat film to each other, said joint portion extending from a rear end of said film shell to a front end thereof in the longitudinal direction of said film shell; (ii) a film bottom member provided at the rear end of said film shell in a longitudinal direction thereof, said film bottom member being capable of being folded into a V-shape along a folding line or of being unfolded so as to expand at a central portion of said folding line in a transverse direction of said film shell, by filling said cartridge with fluid material and (iii) a nozzle provided at the front end of said film shell, said nozzle being formed by sealing said front end of said film shell to provide a nozzle member, and then cutting a tip end of said nozzle member; an outer tube having a tubular shape, into which said cartridge for the fluid dispensing apparatus can be received; a pushing member, which is placed slidably in said outer tube to squeeze said cartridge for the fluid dispensing apparatus; and an outer frame nozzle, which is provided at a front end of said outer tube to support said nozzle of said cartridge for the fluid dispensing apparatus.
According to such features of the present invention, the pushing member, which is slidable in the outer tube, pushes the cartridge received in the outer tube to squeeze the cartridge, thus making it possible to carry out a stable pushing operation for the cartridge so as to prevent the cartridge from partially swelling up. The outer frame nozzle supports the nozzle of the cartridge for a fluid dispensing apparatus, thus preventing an unfavorable movement of the nozzle when the contents in the cartridge are discharged.
In order to attain the aforementioned object, a method for manufacturing a cartridge for a fluid dispensing apparatus, which comprises the steps of: joining opposite side edges of a rectangular flat film to each other to form a film shell having a tubular shape; placing a film bottom member at a rear end of said film shell in a longitudinal direction thereof, said film bottom member being capable of being folded into a V-shape along a folding line or of being unfolded so as to expand at a central portion of said folding line in a transverse direction of said film shell, by filling said cartridge with fluid material; and sealing a front end of said film shell in the longitudinal direction thereof to provide a nozzle member, and then cutting a tip end of said nozzle member so as to form a nozzle.
According to such features of the present invention, it is possible to manufacture the cartridge for a fluid dispensing apparatus only with the use of a film without carrying out a molding method. It is also possible to prevent deep wrinkles from occurring on the film shell, the film bottom member and the nozzle during discharge of the contents.